Sensor network to help monitor homebound seniors

Senior citizens wishing to live independently at home may get a lift from a sensor network designed to monitor their movements and alert caregivers to their status day or night.

Researchers at the University of MissouriSinclair School of Nursing announced a prototype system that uses a combination of motion detectors based on the Microsoft Kinect gaming technology and a hydraulic bed sensor that can measure an individual's pulse, respiration, and restlessness during sleep. Sensors installed in every room and key places, such as inside a refrigerator or kitchen cabinet also measure activity levels. Researchers take a baseline measurement and then collect automated data every seven seconds.

"We don't expect the residents to do anything special," Marjorie Skubic, professor of electrical and computer engineering at the University of Missouri says. "In fact, what we want is for them to be able to live their typical lifestyle pattern and go about their daily activities while, computationally, we are capturing a pattern that represents their usual behavior in their homes-and then we look for changes."

Low-density readings suggest a sedentary person, while high-density readings identify an active person. The motion detectors also determine if a person has left their home, which can be critical information for some medical conditions. Scientists currently are testing the sensor network in TigerPlace, an eldercare facility in Columbia, Missouri.

Sensor technology has advanced exponentially over the years to include pressure, proximity, or temperature as well as motion. And while wearable sensors may be able to track more data than stationary sensors, they are only effective if the subject is wearing the sensor to begin with. This is not always the case for an older adult.

(Marjorie Skubic, professor of electrical and computer engineering at the University of Missouri - Source: University of Missouri

Using the Microsoft Kinect system, the individual's body act as the "controller," with the added support from depth cameras to record movement, researchers noted in their proof of concept. The camera captures a three-dimensional silhouette that represents the moving body. The system then measures and monitors the person's walking speed and length of steps. Short steps that are unanticipated or repeated over time may indicate the senior is getting more frail and thus more susceptible to falls.

"If you detect that somebody's gait is changing, and they are at risk for a fall, you'd like to identify it, so you can provide some kind of intervention, such as physical therapy," Skubic says. "If you can find muscle weakness or imbalance before they cause problems, exercises can be used to strengthen them"

While a commercial application is the end goal, ultimately, says Skubic, the research is designed to deliver peace of mind for caregivers and family members.